Julie discovers that she is pregnant in an upcoming episode after weeks of trying for a baby with partner Brian Packham (Peter Gunn).
Pondering Julie's possible approach to motherhood, Cavanagh told Inside Soap: "Julie will be ridiculous. She'll take everything people tell her literally. It will drive her sister Eileen absolutely mad.
"Julie will work hard at being a mum, but it'll be quite chaotic. She'll probably end up leaving the child in the supermarket! She'll adore her baby, though - it won't be left wanting in the love department."
As previously reported, Brian is initially left wondering whether the baby is really his - as he had a vasectomy some time ago and failed to tell Julie.
Cavanagh commented: "She and Brian have been talking loads about having a child together, and he's seemed really into the idea. The viewers may have been aware that he's been looking a little bit shifty about the whole thing - but Julie hasn't noticed that anything's wrong."
Coronation Street continues on Thursday at 8.30pm on ITV1.
> Coronation Street pregnancy plot revealed
> Coronation Street Julie is not a love cheat, says Katy Cavanagh
> Read more Coronation Street spoilers and news
Watch a preview of Friday night's Coronation Street double bill in the video below: